The present invention relates to a multi-function peripheral, and more particularly to a multi-function peripheral having an image forming function and an image capturing function.
Conventionally, a multi-function peripheral having an image forming function such as a printer function or a facsimile function, and an image reading function such as a scanner function has been known. Such an apparatus can also be used as a copier. That is, an image of an original captured with the scanner function is printed on a recording sheet with the printer function. There are apparatuses which can print the image of the original with scanning the original.
FIG. 1 shows an appearance of such a multi-function peripheral. In this example, the multi-function peripheral has a main body 3, in which the image forming function is implemented. On an upper surface of the main body 3, a cover 5 is provided, in which the scanning function is implemented. Hereinafter, the main body 3 will also be referred to as an imaging unit 3, and the cover 5 is referred to as a scanning unit 5.
The imaging unit 3 employs an electrophotograpic imaging process, inkjet printing process or the like. In either method, the recording sheet is fed in an auxiliary scanning direction which is perpendicular to a main scanning direction (i.e., in a laser scanning direction in the former case, or in a direction where a carriage mounting an inkjet head reciprocates) so that a two-dimensional image is formed.
The scanning unit 5 typically employs an image capturing element such as a CCD (Charge Coupled Device) or a CIS (Contact Image Sensor). In one type, the image capturing element is fixed to the apparatus, and the original is fed with respect to the apparatus. In another type, the original is placed on a predetermined position and the image capturing element is moved with respect to the original.
The image capturing element is generally configured such that a line of image extending in the main scanning direction, which is perpendicular to the feeding direction of the original (or the image capturing element), and as the image capturing element is fed relatively to the original from one end to the other end of the original, the two-dimensional image formed on the original is captured. In the apparatus in which the image capturing element is moved, it is returned to its initial position after an original is scanned.
FIG. 2A shows directions in which the image capturing element and the carriage move. FIG. 2A shows moving directions of the image capturing element and the carriage viewed from a front side. As shown in FIG. 2A, in the imaging unit 3, a carriage 11 moves in a direction indicated by arrow A in a horizontal plane (which is a plane perpendicular to a plane of FIG. 2A and is parallel with a right-and-left hand direction in FIG. 2A), and forms an image on a sheet with use of the inkjet printing method.
The scanning unit 5 is configured such that a CCD 13 moves in a direction indicated by arrow A in the horizontal plane to capture a two-dimensional image of the original placed on a upper surface of the main body 5. After the image is captured, the CCD 13 returns to its initial position which is the position shown in FIG. 2A. In this example, the scanning unit 5 is capable of scanning a color image.
When the scanning function and the image forming function are actuated simultaneously in the multi-function peripheral configured as above, as the carriage 11 reciprocates, vibration is generated, which may deteriorate a quality of an image scanned by the scanning unit 5. That is, a moving speed of the imaging element 13, which should move at a predetermined constant speed, may fluctuate due to the vibrations generated by the reciprocal movement of the carriage 11 and causes a color shift of the captured image. Even when the CCD 13 does not read a color image, the uneven moving speed deteriorates the scanned image.